More than 4,700 stray dogs couldn’t be reunited with their owners due to outdated chips, according to animal charity Dogs Trust.
A total of 37,283 dogs were left languishing in local authority kennels in the 12 months to March 2016 - and one in eight were there simply because their microchips had not been updated by their owners.
Dogs Trust’s annual survey of local authorities also found that 3,463 stray dogs had been put down in the last year.
Iit became a legal requirement in April for all pet dogs to be microchipped with current contact details. Owners who fail to microchip their pets with up-to-date contact details face a fine of up to £500.
However, the survey found the number of stray dogs taken in by councils had decreased from 102,516 to 81,050 - a drop of 21 per cent.
16,447 of these animals were microchipped - and 9,052 were able to be reunited with their owners.
Adrian Burder, Dogs Trust’s chief executive, said: “To discover that the number of stray dogs in the UK is down from last year is promising, but with over 37,000 dogs remaining unclaimed in council pounds last year, it’s clear we still have work to do.
“Local authorities work tirelessly caring for stray and abandoned dogs each year, but sadly they just don’t have the resources or manpower to care for every stray dog in the UK.
“Stray dogs that find themselves at Dogs Trust are the lucky ones, as we will never put a healthy dog to sleep, but not all of the unclaimed dogs are so fortunate.”